Mucuna pruriens Detoxification through Ensiling

Mucuna pruriens is grown for food and feed despite its L-Dopa concentration (2-6% by wt), which is toxic to monogastrics. The aim of this study was to determine if the L-Dopa concentration of Mucuna could be reduced by ensiling. The objective of Experiment 1 was to examine how long it takes to decrease the pH of ensiled Mucuna to 4.5. Crushed Mucuna beans (6 mm) were ensiled in the dark at room-temperature (18 to 25°C) for 0, 3, 7, 14, 21, and 28 days in vacuum-sealed bags. A pH of 4.5 and an L-Dopa concentration of 1.3% (54%) reduction) were recorded after 28 days. The objective of Experiment 2 was to study the effect of particle size of ensiled Mucuna on L-Dopa concentration and fermentation and nutritional characteristics. Ensiling Mucuna that had been ground to particle sizes of 2, 4 and 6 mm for 28 days decreased the L-Dopa concentration from 2.8%) in the unesiled bean to 1.2, 1.6, and 1.1%, respectively. Ensiling also reduced the water-soluble carbohydrate (WSC) concentration and pH and increased the ammonia-N (NH3N) concentration. Neither ensiling nor particle size affected concentrations of ether extract (EE; 5%), CP (23-25%), starch (38-40%), and neutral detergent fiber (NDF; 17- 20%). Dry matter losses (< 1%) and mold or yeast counts were unaffected by particle size. Aerobic stability was maintained beyond 657 hours in all treatments and the lactate:acetate ratio of all samples exceeded 3.0. In conclusion, ensiling Mucuna bean for 28 days reduced the L-Dopa concentration by 43 to 61% while preserving most nutrients. Particle size had minimal effects on nutritional composition or fermentation indices.